The present invention relates generally to optical information processing, and more particularly to an optical switching device based upon stable, non-absorbing optical hard limiters.
In today""s information age, optical communication technologies are being used more and more frequently for transmitting information at very high speeds. Traditionally, information processing equipment (such as switches, routers, and computers) process information electronically. Therefore, optical communications are often converted into electronic form for processing by the information processing equipment. This electronic processing is slow relative to the speed of the optical communications themselves, and thus often becomes a xe2x80x9cbottleneckxe2x80x9d of optical communication and processing systems.
Optical information processing systems process information optically without the need to convert the information to an electronic form for processing electronically. One challenge in an optical information processing is the switching of optical information from an input to one of a number of outputs. Traditionally, optical information switching would be accomplished by converting the optical information into an electrical form, switching the information using traditional electronic means (e.g., routing based upon an address), and converting the switched information back into an optical form for further processing by the optical information processing system. This technique for switching optical information is limited by the speed of the electronics and becomes unsatisfactory as optical communication speeds increase.
Packet switching using all-optical logic has been explored using in band addressing systems (U.S. Pat. No. 5,739,933) and out-of-band addressing systems (U.S. Pat. No. 5,488,501, U.S. Pat. No. 4,894,818).
In accordance with one aspect of the invention, an optical switching device based on stable, non-absorbing optical hard limiters optically switches optical information from an input to a number of outputs based upon address information contained in the optical information. The optical switching device optically detects the location of the address bits in the optical information, optically samples the address bits, optically decodes the sampled address bits, optically activates an output based upon the decoded address bits, and optically outputs the optical information over the activated output.
In one exemplary embodiment of the invention, the optical information is split into successive copies with approximately one bit time delay between successive copies. Each of a number of successive copies is fed into an optical sampler, and the optical samplers are clocked at an appropriate time to sample a different address bit.
In another exemplary embodiment of the invention, the optical information is sampled using an optical shift register.